SB,

What you have there (and this is the second time I've seen this done on a Super Sport) is a 3 piece conversion using a BB spindle Schwinn had made to convert their Town and Country Twinn (5 speed tandem) up to a Twinn Sport (10 Speed tandem). I have the Twinn Sport and both BBs use this BB arrangement.

I believe the crank also came from this set up. It was the front or captain's crank, which on this bike had a righthand chainring instead of the usual lefthand tandem style. While the captain's crank on my Twinn Sport had only one 42 tooth ring, it could handle a double and was drilled and threaded for a granny gear.

Does all this make sense? Well maybe a few pictures will help. Here's the captain's crank. You can see the granny gear mounting holes, the same BB setup, and I believe it looks to be the same Sugino crankset.


Here's a pic of the front half of the drivetrain so you can see how it was set up. They used a different crankset for the stoker's position.


Here's the inside of the stoker's crankset showing the BB spindle. Best of luck and I hope this was helpful.